You'll get better results with Irish Moss if you rehydrate it before tossing it in. I usually put a little water in a coffee cup with the Irish Moss before I start the boil and then toss it in at 15 minutes before the end.
Better yet get the Whirfloc tablets and just toss those in in the last 5 minutes. They work much better and you don't have to worry about measuring.
Drinking on the keg: BPA, Brown Ale, Dry Mead, Wee Heavy aged on Oak, CAP
Drinking in the Bottle: